Flexible suspension



June 16, 1942. 1'. GRISWOLD. JR 5 FLEXIBLE SUSPENSION 7 Filed Sept. 21,1940 2 Sheets-Sheet 1 FIG. 2

, INVENTOR June 6, 1942- T. G RISWOLD. JR

FLEXIBLE SUSPENSION Filed Sept. 21, 1940 2 Sheets-Sheet 2 1%., amm BYPatented June 16, 1942 FLEXIBLE SUSPENSION Thomas Griswold, .iin,Midland, Mich. I Application September 21, 1340, Serial No. 357,634

4 Ciaims.

My invention concerns flexible suspensions for swingable objects, e. g.means for attaching the supporting rope or other tension member of aswing to the support therefor. It concerns more particularly a form ofsuspension in which there is no hinge pin subject to rubbing, nor arethere roller bearings or other devices to lessen the friction of such apin in the attachment. It still further concerns a form of suspensionpractically frictionless and squeakless, requiring no lubrication andadapted, among other uses, for the flexible connection of playgroundswings to their overhead supports.

It has been found by experience that hinged suspensions, in which thereis a pin, deteriorate with wear, introduce appreciable friction wherebythe swing is retarded, and squeak objectionably unless oiled. Theobjections to such a method of hanging a swing have been overcome inpart by the introduction of roller bearings for the pins. Suchconstruction constitutes an improvement over the pin hinge form, butsuch suspensions are elaborate and costly. They operate in one planeonly and side swing must be accommodated by sliding of chain links,clevises, clevis pins, or other joints in the flexible continuation ofthe swing rope up to the roller bearing in the suspension.

I have developed a novel form of suspension particularly suited, amongother applications, for

use in connecting side ropes of swings in playgrounds to the overheadsupports, but generally adaptable to any and all uses where one objectis to be swung while attached to another. This device comprises aflexible member such as a rope, strap or chain attachable to theswingable object, e. g. to the upper end of the side rope of a swing,the flexible member being held in a hanger adapted to grasp the upperend of the flexible member and the overhead supporting A strap whichwill permit the strap to swing sidewise as well as toand--fro. Thehanger which holds the strap will be provided with outwardly flaringcurved skirts upon the surfaces of which the strap may wrap and unwrapas it swings back and forth under load. These curved skirts reduce thebending stress upon the strap to a low value and insure it a long life.

I will now describe my invention in' several forms, all forms adaptablefor use on playground swings, and I have illustrated my invention byseven figures in the accompanying drawings.

Referring now to the drawings:

Fig. 1 is a side view of an assembled suspension. Fig. 2 is a front viewthereof. Fig. 3 is a side view of a strap. Fig. 4 is an edge Viewthereof. Fig. 5 is a side view of an alternative form of suspension.Fig. 6 is a face view of Fig. 5. Fig. 7 is a side view of the flexiblemember of the suspension shown in Figs. 5 and 6.

In l and 2 the strap is shown broken to reduce the height of the figure.In Figs. 3 and 4 the strap is shown full length as required forapplication. In Figs. 5 and 6 the flexible member is out off to reduceheight of the figure. In Fig. 7 the flexible member is shown fulllength. Similar reference figures will be used for like parts in allfigures.

In the drawings, I represents a conventional horizontal pipe support forplaygroupnd swings. Each side rope suspension here shown comprises apair of identical clamp members 2 held in clamping relation upon thepipe l by the clamp bolts 3 and 4 which bring the members 2 intogripping contact with the pipe surface, preferably at restricted lands5. The clamping members 2 are flared out into arc-like skirts 211.Between the members 2 and pierced by the bolt 4 is the flexible member,shovm here as a strap 6. The strap may be made of any suitable flexiblematerial such as woven wire, fiber such as cotton cord or duckimpregnated with rubber or other suitable compound, or the strap may bea flexible synthetic resin or compound having suitable strength,flexibility, and durability. I have found that a piece of impregnatedcotton belting makes a very satisfactory and durable strap for a playground swing suspension. For such a strap I prefer to reinforce the twoends with metal plates applied to the two faces and secured thereto byth ough rivets, either with or without a bonding or cementing material.These reinforcing plates are shown in Figs. 1 to 4, inclusive, at l forthe lower end of the strap and at 8 for the upper end thereof. The strapand its plates are perforated as shown with a hole for the through bolt4 in the upper end and a hole in the lower end for attachment to theside rope of the swing by means of a suitable link or equivalent.

For the type of construction shown in Figs. 1

to 4, inclusive, I prefer that the clamping members 2 of the hangershall come together at the faces 9 and shall have a recess I slightlywider than the overall thickness of the strap at the plates 8. I preferfurther that the curvature .of the flaring wings shall startsubstantially tangent to the strap when hanging in a vertical position.With this arrangement and the bolts 3 and 4 tightened up to securelyhold the hanger to the pipe, the strap 6 will be loosely, but somewhatclosely, held in the recess I0 hinged upon the bolt 4, but when thelower end of the strap is moved to-and-fro with the swing the strap willbe wrapped upon the arcs of the skirts without sudden or extreme flexureat any point. The strap will also pivot on the bolt 4, if necessary, toaccommodate any lateral motion of the swing without putting a sidewisebending stress upon the strap.

In use, this swing attachment is noiseless, practically frictionless,and durable. It is cheaply made, easily applied, employing but two boltsper unit.

Other modifications of structure may be made to suit variousrequirements and uses without departing from the spirit of my invention.

One such modification is shown in Fig. 2 by the dashed lines 21) which,for a suspension not subjectto lateral motion of the swing and' flexiblemember of the suspension, represent the limits to which the skirts maybe confined, no flare of skirts being necessary.

Another modification is shown in Figs. 5 to '7, inclusive. Here thestrap is replaced by a flexible rope 6a., which may be, for instance, aflexible steel or bronze wire cable. The hanger is in two identicalhalves as in the first description, but the flaring skirts 2c, are ofhalf bell-shaped funnel form. Two clamping bolts may be used above andbelow the pipe support. The two hanger members contact along the line 9,each furnishing a half of the funnel. The wire rope flexible member maybe expanded at the ends as shown by tapered pins 8a to form conicalenlargements. The upper conical end of the cable seats in a conicalsocket I4 in the hanger. lower enlarged end seats in a correspondingconical socket [5 in the socket eye 1 adapted to connect with a siderope of a swing or with any other s'wingable object. Two bolts, I2, inlugs l3- serve to hold together the lips of the bellfunnel.

This formof suspension permits free lateral and to=and--fr.o motionwithout hinge pin action.

The members 2 may be conveniently made in iron, preferably malleablizediron, although other metals or material may be used.

Various types of flexible members may be used,

The l such as thin flexible metal bands or straps, link chain, etc. Thecable shown in Fig. 6 may be in the form of a loop or hair pin, ifdesired.

Where, in the claims, the word skirt or skirts is used, it shall beunderstood to mean the funnel construction and/or the flat curvedconstruction.

I claim:

1. In a suspension of the character described, a hanger for a flexiblesuspension member comprising two clamp elements clampable upon a supporttherefor, a curved skirt extension of each said clamp element dependingbelow the clamped assembly, the two skirts being in opposed relation toeach other, and means to secure one end of a flexible suspension memberin said assembly between said opposed skirts in approximate tangentialrelation thereto.

2. In a suspension of the character described, a hanger for a flexiblesuspension member comprising two clamp elements clampable upon a supporttherefor, a flaring curved skirt extension of each said clamp elementhaving a half bellshaped funnel. form depending below the clampedassembly, the two skirts being in opposed relation to each other andforming in assembly a flaring bell-shaped funnel, and means to secure aflexible suspension member in said assembly between said opposed skirtsin approximate tangential relation thereto.

3. A suspension for playground swings comprising a hanger for a flexiblesuspension member, having two clamp elements clampable upon the swingsupport, a curved skirt extension of each said element depending belowthe clamped assembly, the two skirts being in opposed relation to eachother, means to secure one end of a flexible suspension member in saidassembly between said opposed skirts in approximate tangential relationthereto, and means to permit fastening a swing tension member to theother end of said flexible suspension member.

4. In a suspension of the character described, a hanger for a flexiblesuspension strap comprising two clamp elements clampable upon a sup porttherefor by bolt means adapted to draw said elements together to enclosesaid support seated upon seats therefor in said clamp elements, aflaring curved skirt extension of each said clamp element dependingbelow the clamped assembly, the two skirts being in .opposed relation toeach other, and means to secure one end of a flexible strap between saidso clamped elements to depend between said opposed flaring curved skirtsin approximate tangential relation thereto.

THOMAS GRISWOLD, JR.

